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Prevalence of the use of drugs specific to attention deficit disorder with or
without hyperactivity (ADHD) in individuals 0 to 25 years of age in Canada
English summary
Une production de l
’Institut national d’excellence en santé
et en services sociaux (INESSS)
SEPTEMBER 2017
This is the English summary of the guidance entitled Prévalence de l’usage des médicaments
spécifiques au trouble du déficit de l’attention avec ou sans hyperactivité (TDAH) chez les Canadiens de 25 ans et moins published in September 2017.
The complete version of this guidance (in French) is available on the website of INESSS in the Publications section.
Équipe de projet Auteurs
Éric Tremblay, B. Pharm., M. Sc.
Jean-Marc Daigle, M. Sc.
Collaboration
Mélanie Turgeon, B. Pharm., M. Sc.
Extraction des données IMS Health
Analyses statistiques Jean-Marc Daigle, M. Sc.
Coordination scientifique Marie-Claude Breton, Ph. D.
Direction
Sylvie Bouchard, B. Pharm., D.P.H., M. Sc., M.B.A.
Repérage d’information scientifique Éric Tremblay, B. Pharm., M. Sc.
Jean-Marc Daigle, M. Sc.
Soutien documentaire Flavie Jouandon
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SUMMARY
Introduction
The Minister of Health and Social Services is concerned about the use of drugs specific to attention deficit disorder with or without hyperactivity (ADHD) in Québec, which is apparently more common than in the other Canadian provinces. The Minister asked INESSS to provide an overview of the use of ADHD-specific drugs in Québec, and he also wanted the current situation in Québec to be clarified in relation to that in the other provinces. The overall objective of this overview is therefore to calculate the prevalence of the use of ADHD-specific drugs among individuals 0 to 25 years of age by Canadian province from April 1, 2014 to March 31, 2015.
Methodology
We conducted a cross-sectional study using IMS Health and Statistics Canada data. The prevalence of the use of ADHD-specific drugs in the entire 0-to-25-year-old population was calculated for the 10 ADHD-specific drugs together and for each one separately. The distinct number of users of ADHD-specific drugs was estimated by IMS Health from community pharmacy data. These data have a national coverage rate of approximately 70.7% (74.3% in Québec) in terms of the number of prescriptions. The denominator used to calculate the prevalence was determined from 2014 population estimates provided by Statistics Canada. Usage prevalence was described on the basis of province, user age and sex, and ADHD-specific drug used. A prevalence rate and its 95% confidence interval were estimated for each of the values for the variables considered in the
analyses. The usage prevalence for the 10 ADHD-specific drugs combined and for each one separately was adjusted for the age distribution in Québec during the study period.
Results
The age-adjusted prevalence of the use of ADHD-specific drugs in the 10 provinces ranges from 1.95% to 6.44% and is 3.26% nationwide in Canadians age 0 to 25 years.
The prevalence of the use of the 10 ADHD-specific drugs decreases to 2.39% in Canada when Québec is excluded from the calculation. Québec stands out from the other
provinces with the highest prevalence of such use in the country, both overall and after stratification by sex. However, the situation in Québec is nuanced when the usage
prevalence is analyzed by age group and ADHD-specific drug. It is only in the 0-to-5-year age group that the prevalence is lower in Québec than that in at least one other province.
Usage prevalence by drug in Québec is higher than the Canadian value for all the drugs, except intermediate-acting dextroamphetamine. For five of the 10 ADHD-specific drugs, namely, Concerta and its generics, Biphentin, lisdexamfetamine, atomoxetine and guanfacine, the age-adjusted usage prevalence among 0- to 25-year-olds is higher in Québec than in all the other Canadian provinces.
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Conclusion
This overview involved calculating the age-adjusted prevalence of the use of ADHD- specific drugs in Canada by province, age group and sex in the entire 0-to-25-year-old population. The broader coverage of long-acting ADHD-specific drugs in Québec than what was observed elsewhere in Canada and free access to drugs for children and full- time students aged 18 to 25 years enrolled in Québec’s public prescription drug
insurance plan (PPDIP) could explain the higher prevalence of the use of ADHD-specific drugs in this province. However, the magnitude of the difference in the prevalence of the use of these drugs in 0- to 25-year-olds in Québec compels one to investigate
explanatory hypotheses other than that of access to drugs. These include too hasty a diagnosis and an unsatisfactory medical follow-up.
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